Thread Tools
Aug 14, 2011, 02:46 PM
Registered User
KoneWone's Avatar
Thread OP
Quote:
Originally Posted by Boomer1
A Yamaha will be going in the classifieds later today. If you are interested.
Again, the shipping is the deal killer.
Hi Guys, Boomer your beloved Yamaha up for sale ! man-o-man you be bewitched like myself, love to buy it but "the boss" says enough boats & shipping would be the real killer ...but thanks all the same.

Today decided to get into it and start with the sheeting circuit, to help explain the genoa function have posted schematic of the circuit which controls the Genoa and Main from single ring in the circuit which travels from port to starboard off the closed loop circuit running from RMG winch that uses 90 mm drum.

The Sprinta-RC uses an RMG for only one reason, itís the only winch on the market that provides the 9 rotations @ 10 kg.cm of the huge drum to fully sheet in from port to bow tack (1,380 mm travel) and it does it 1.8 seconds, Christian says he always on the look-out for less expensive winch, but yet to find anything else thatís up to the job.

There is a second servo (other being rudder) that is used only for main sheet trimming independent of the Genoa, where you can have few cms trimming adjustment under sail for leaking little when running or pinching close-hauled, it does have small influence on main twist but not much.

As Main & Genoa share same sheeting circuit, TX control is as normal left stick where when centred up & down sheeting is full out for running, stick down is closed hauled port & stick fully up closed hauled starboard. Iíve mixed the main sheet trimming with sheeting stick.

When going about the main does go loose and this is where skill in timing comes into play by the skipper just like a real boat where need to trim main to avoid losing main boom position, this can be done by either programming up/down sheeting stick to have side-to-side main trimming control or program the transmitter trimming adjuster to perform this function.

Sailing the boat takes some getting used too which is just matter of practice, to become a master takes lot of practice to learn the skill.

This is a one design class boat, where every boat is exactly the same for regattas the only real personal adjustment is in how you wish to program set-up transmitter for Genoa and main sheet trimming controls.

Cheers K1
Sign up now
to remove ads between posts
Aug 14, 2011, 03:27 PM
Boomer1
Boomer1's Avatar
Alan.
The Yamaha belongs to a person I know that is selling one! No chance of mine going up for sale! It is a part of the family.

The Yamaha currently listed in the classifieds of this forum, belonged to great guy, you passed on not to long ago. His wife Victoria is hoping to sell it to someone that will get to enjoy it. Richard loved the boat, but sadly, never really got to enjoy it.

So any of you fellows out there that have been looking for one of these masterpieces, check out the ad. Send her an e-mail - can't win if you don't get in the game! She is in Florida, so domestic shipping makes more sense, or if you are that area, picking it up would great.

It is a very nice boat for sure. I have two now, and my next treasure I am looking toward, is the Sprinta!

Boomer
Aug 20, 2011, 09:38 PM
Boomer1
Boomer1's Avatar
Alan
The Yamaha was sold went for full asking price. Need more build pictures!!
Boomer
Aug 22, 2011, 12:57 AM
Registered User
KoneWone's Avatar
Thread OP
Quote:
Originally Posted by Boomer1
Alan
The Yamaha was sold went for full asking price. Need more build pictures!!
Boomer
Glad to hear ...sorry I'm bit of road warrior (bus travel) will have more build pics coming weekend after I get back home.

Cheers Alan
Sep 04, 2011, 01:28 PM
Registered User
KoneWone's Avatar
Thread OP

Sprinta RC - main sheeting


Hi Guys, now back and onto boat & start with the main sheeting.

Unlike conventional RC yachts where main sheeting comes directly off the servo or winch, the Sprinta RC system works off the closed loop circuit that has small ring which the main & genoa are attached to.

As the boat tacks the circuit moves ring from one side of the deck to the other taking with it the Genoa the main sheets.

The black line in first pic is the main sheet which runs through a block at the bow & then through a tube under the mast foot then through few loops under the main boom to another block at end of the boom where it cahnages direction again to a block on the traveller bar.

Unfortunately, you can't move the block on the traveller where it is fixed in the centre, however, there is a servo on starboard side of the cabin that the main sheet ends. the fore & aft that the servo has allows the main to be sheeted in or out, independant of the Genoa.

This is the part of the boat I feel can do with improvement because as you go about (tack or jibe) as the sheeting changes sides, the main sheet goes completely loose, have seen ideas where the sheeting servo has been used as a braking driven, holding the main sheet as boat goes about.

Until I try the boat in the water for some time, I can't say how critical this point is.

Cheers Alan
Sep 05, 2011, 01:58 PM
Registered User
KoneWone's Avatar
Thread OP

Sprinta RC - Rigging


Moving onto the rigging is quite straight forward with few little nice ideas.

Firstly, I'm using stainsteel tracer wire (personal choice) as I find it provides better transport handling with less tangles. The Genoa has luff pocket which the front stay slips easily through the pocket and attaches to "L" hook at the bow with quick bullet swivel.

The top of the forestay just clips into one of four holes pre-drilled into the mast and gives you 15 mm mast tilting.

The Spreaders are brushed Stainless, little heavy but strong as I come to expext from German engineering, hole is pre-drilled into the mast again and the tongues nicely over-lap inside the mast providing fast and solid hand fitting, note the tip of the spreaders have nice round tips so the Genoa does not get caught when going about.

These have got to be the best chain plates I have ever seen, beautifully made out of stainless again. The base is socket design with slot and it is secured to the deck that, the shroud base is ball design that just simply slips into the socket on angle and locks into place.

Just above the ball you can see "V" shape machined into it, this help the sheeting curcuit does not ride up the shrouds ...very cool Naturally you have thread adjustment for tension and to finish it off there nice heavy plastic tube over the shroud to protect the sails.

Finally we have the backstay which uses series of blocks that give traditional big boat look with nice single & double blocks. The only thing I don't really like is the use of polyester lines around the boat, stretches like hell so when I get around to finding some dracon line, I'll replace them.

Rigging & de-rigging takes about 2-3 mins if you take your time, very nice simple ideas help have you quickly in the water when you arrive at the water.

Cheers Alan
Sep 05, 2011, 05:52 PM
Boomer1
Boomer1's Avatar
Alan
Now I know why these boats are so expensive. Really great hardware! May have to go back to work! I can't believe I said that!

Terrific pictures! Thank you
Boomer
Sep 06, 2011, 01:47 AM
Registered User
KoneWone's Avatar
Thread OP

Sprinta RC - Vang


Quote:
Originally Posted by Boomer1
Alan
Now I know why these boats are so expensive. Really great hardware! May have to go back to work! I can't believe I said that!
And he's me praying for early retirement this side of the pond it is not so expensive compared to other available options and considering you have all top notch hardware e.g RMG, professional sails etc. it is the greatest value for your money.

Coming to the Vang, this is the only personal change I've made on the boat, standard hardware supply is for soft vang fitting & my choice is to go for hard vang as I feel in light air the soft vang is not effective as the main sail stays flat under the weight of the boom & sail ...personal choice.

The tension for the main luff is via neat simple ring bracket that is screwed to the base of a "J hook" that holds the tack of the mainsail. A line comes from cockpit through two rings mounted on the deck and to change luff tension from cockpit area.

Once again to give it that big boat look & feel there is a imiation deck winches that are spring loaded (in case any other lines should catch here) and the end of vang line tie-off using small velco patches in the cockpit area that have compass label covering ...very cool

Cheers Alan
Sep 06, 2011, 02:12 AM
Registered User
KoneWone's Avatar
Thread OP

Sprinta RC - Cockpit water exhaust


Now here is great feature ... Looking into the cockpit you can easily imagine in rough weather that water it will get trapped in the cockpit, I estimate it holds roughly 1.5 litres of water = 1.5 Kilo extra weight, not what you want !

You can see on the floor of the cockpit there are two holes, these are drainage holes which are connected by plastic tubes (inside hull) to two exhaust holes on underside of hull near the rudder.

When sailing any water that gets into the cockpit area is sucked through the exhaust by low pressure vortex that is created as the hull moves through the water ... super cool idea

Cheers Alan
Last edited by KoneWone; Sep 06, 2011 at 02:18 AM.
Sep 06, 2011, 12:30 PM
Big Boats Rule!
boater_dave's Avatar
The boat looks amazing, but...
On the deck layout pic you have the port side cabin top winch wrapped backward. Winches (Harken, at least) all go the same direction around.
I have been pondering the sheet setup for several days. How do they connect the main sheet to the loop for the jib? Does it pass through a fairlead, or am I missing something?

Dave
Sep 07, 2011, 03:33 AM
Registered User
KoneWone's Avatar
Thread OP
Gidday Dave, thanks for the heads up on putting the lines on wrong way around the imitation deck winches, I 'll fix that one

Quote:
Originally Posted by boater_dave
I have been pondering the sheet setup for several days. How do they connect the main sheet to the loop for the jib? Does it pass through a fairlead, or am I missing something? Dave
Must admit it took me few days looking at pics to try and figure out the sheeting, only when I saw it first hand did the penny drop & I've tried to make it simple but obvouisly failed

Have attached the sheeting diagram again as reference with few mods that will hopefully make it clearer, if I fail again please tell me & I'll try another approach.

The "Green" line is the sheeting curcuit which runs via the drum winch and the Genoa & Main sheeting are tied to this curcuit ring. As the winch rotates the curcuit it ring moves from one side to the other with and Genoa & Main sheeting attached (pic attached showing small ring)

The "Red" line is the main sheeting, that is attached to the circuit ring.

The "Blue" is for main sheeting trimming and attached to arm servo, which gives independant adjustment of the main boom seperate to sheeting circuit.

The "Black" line is the Genoa sheeting that is attached to the curcuit ring.

There is no fairlead or Jib as the Genoa overlaps the mast by 150%, therefore the traditional Jib & boom can't not work.

This RC yacht was intentionally designed to have the same set-up & sailing charteristics of the orginal sized yacht (or as close as) using traditional big boat Genoa set-up, to my knowledge it is the only commercailised RC yacht available anywhere in the world that does this ... and with high quality construction with hardware at more than realistic price.

Cheers Alan
Sep 07, 2011, 05:00 AM
Registered User
KoneWone's Avatar
Thread OP

Sprinta RC - Reefed Main


Another great feature is that you can reef the main sail down two levels, see the holes in the main sail. Just need release main sail bolt rope at the head crane to let bolt rope slide down inside the mast groove and then to roll-up foot of the main to either of two levels.

Remember the ď JĒ hook at tack of the main, there is one at the clew as well and you just hook them into the reefing holes on the main sail then try elastic chord around the centre hole of rolled up main reef and your good to go.

Christian tells me that he sails up to 11-15 knots of wind before having to think about reefing the main.

The keel is 4 kiloís (lead) and bolts directly into shaft and locked down with wing nut with easy access inside the cabin. The rudder is 1 kg (lead) that bolts in quickly as well.

Options available is movable ballast, in pic below you can see I have two each approx 850 grams and you can see they slot nicely into slots in the cockpit floor or you can move them inside the cabin, here I need to find right place to get her sailing on her water-line and have best helm balance.

The Genoa as on big boats uses a traveller each side of the boat which guide the sheets via the circuit, the traveller can be move fore & aft 6 cm to adjust draft and leech tension for different wind conditions.

There we go assembly finished, graphics on and ready for her maiden voyage ...

Cheers Alan
Sep 07, 2011, 09:48 AM
Big Boats Rule!
boater_dave's Avatar
I think I get it. The main sheet is attached to the continuous loop in the same place as the genoa sheet. Starting on port tack, as pictured, the green line is at the end of it's clockwise movement and all sails are sheeted in tight. As you loosen the sheet the green line rotates counter clockwise and the both sails go out. As the attachment point comes around the forward portion of the loop the genoa clew is pulled around the mast and the main sheet begins pulling again. Did I get it right? It has given me an idea for a schooner I am rebuilding. Thanks for the help, and the photos are great too!

Dave
Sep 07, 2011, 11:34 AM
Boomer1
Boomer1's Avatar
Alan
Great build! Bet you can't wait to get her in the water! Hope you are able to shoot some video to share with us!
The boat is more impressive now after seeing your detailed build photos.
Thank you
Boomer
Sep 07, 2011, 12:21 PM
Registered User
KoneWone's Avatar
Thread OP
Dave you've got it mate !! .... the key to this Genoa system is the speed going close hauled side to side as you tack, the Sprinta does complete curcuit in 1.8 seconds using 90 mm drum that runs off RMG winch, it is the only winch that can handle these speeds and sail forces of 800 cm2 sail area.

Anything less in speed and you lose too much speed when tacking

Boomer, I've got lot of projects on my hands at the moment with Italian IACC 120 cup coming up end of this month, I'm like a one-armed wall paper hanger at the moment but I'll try for a movie (no promises) but will have photo's & boat handling report within next few days.

Cheers Alan
Last edited by KoneWone; Nov 05, 2011 at 02:42 AM.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Article Pro Boat RC Retrieval Decoy Review: Great for a Child's First RC Boat Michael Heer Dock Talk 36 Jan 14, 2014 10:09 PM
Found Rc Logger 107_RC Rc Logger Digital Pitch Gauge ronzer Aircraft - General - Miscellaneous (FS/W) 1 Jul 03, 2011 09:11 PM
Discussion CRRC GF55II 55cc rc Gas Engine for Rc aircraft& muffler l glow plug Engines 0 Jun 26, 2011 06:53 PM
Discussion Can I use a RC Plane Transmitter for my RC Boat? chevchelios Dock Talk 2 Mar 03, 2011 11:38 PM